Air cleaner box for straddle vehicle

ABSTRACT

A straddle vehicle having an under bone frame structure in which a portion positioned in front of a seat is recessed downward. An air cleaner is disposed behind a cylinder block of an engine to be interposed between a right and a left seat rail. An upper portion of the air cleaner projects upward more than the seat rails. A top of the air cleaner is covered by a seat front cover that divides a space defined in front of the seat. The air cleaner includes a lid and a cleaner case that is more tall than is broad. For maintenance work, the seat front cover is removed, and the lid is taken out obliquely upward forward.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a straddle type vehicle such as a motorcycle,for example.

2. Description of Related Art

Conventionally, in straddle type vehicles such as motorcycles etc., theso-called under bone type frame structure is known. In a straddle typevehicle having the under bone type frame structure, an area existing infront of a seat is greatly recessed downward to define a relativelylarge space in the front area of the seat. Thus, according to the underbone type vehicle, a rider can easily get on and off the vehicle. On theother hand, however, in the under bone type vehicle, vehicle componentsneed to be efficiently disposed under the seat to define such a largespace in front of the seat.

Patent Document 1 discloses an under bone type motorcycle. Themotorcycle includes a main frame obliquely extending downward rearwardfrom a head pipe, and seat rail frames obliquely extending upwardrearward from a rear portion of the main frame. The main frame supportsan engine under a suspended condition. A fuel tank is mounted on theseat rail frames, and a seat is disposed above the fuel tank. Acarburetor is disposed in the rear of the engine, and an air cleaner isdisposed in the rear of the carburetor. The air cleaner is positionedbelow the fuel tank. A rear portion of the air cleaner and a frontportion of the fuel tank together align vertically. Also, the aircleaner are placed between the right and left seat rail frames. A topend of the air cleaner is generally positioned at the same height as theseat rail frames.

[Patent Document 1] JP-A-Hei08-67285, laid-open patent applicationpublication.

By the way, the air cleaner needs periodical maintenance. For example, afilter of the air cleaner should be periodically cleaned or replacedwith new one. In the motorcycle, the air cleaner is disposed below thefuel tank. Maintenance work thus is made by an approach from a lateralside location.

However, a user is compelled to take a stooping position or a squattingposition for making replacement work, for example, of the filter,because the air cleaner is placed at a relatively low position.Therefore, some of the users can be uncomfortable in the maintenancework of the air cleaner.

SUMMARY OF THE INVENTION

This invention is made under the circumstances, and an object thereof isto make maintenance work of an air cleaner easier in a straddle typevehicle having the under bone type frame structure.

A straddle type vehicle according to the present invention is directedto a vehicle comprising a vehicle body frame including a head pipe, afront frame connected to the head pipe and obliquely extending downwardrearward, and a rear frame connected to the front frame and obliquelyextending upward rearward, at least one of the front frame and the rearframe having a pair of spaced portions spaced apart in a transversedirection of the vehicle. The vehicle included an engine having acrankcase and a cylinder block extending forward (including ahorizontally forward direction and an obliquely forward upwarddirection) therefrom. The engine is supported by the vehicle frame. Thevehicle includes an air cleaner positioned behind the cylinder block andbetween the spaced portions in the transverse direction, a seatsupported by the rear frame, and a seat front cover that is detachablypositioned below and ahead of the seat and has a concave, in a sideelevational view, to define a top open space in front of the seat forcovering a top of the air cleaner, wherein a portion or the whole of theair cleaner is mounted to be insertable and removable by an approachfrom an upper location or an obliquely front upper location.

According to the straddle type vehicle, a space located above the aircleaner becomes open when the seat front cover is removed. Thus, aportion or the whole of the air cleaner can be taken out upward orobliquely upward forward. Also, under the removed condition of the seatfront cover, the portion or the whole of the air cleaner can be insertedby the approach from the upper location or the obliquely front upperlocation. The maintenance work for the air cleaner thus can be made bythe approach from the upper location or the obliquely front upperlocation. Accordingly, the user can make the maintenance work in acomfortable position, even though the air cleaner is placed at therelatively low position.

Preferably, the air cleaner has a box shape such that a length thereofin a vertical direction is longer than any one of a length thereof in afore to aft direction and a length thereof in the transverse direction.

A capacity of the air cleaner can be therefore larger without increasinga length of the vehicle in the fore to aft direction or a width thereof(a length in the transverse direction). Additionally, because the aircleaner can be inserted and removed by the approach from an upperlocation or an obliquely front upper location, unlike any work made byan inserting or removing approach from a lateral side location, theattaching and detaching work does not become difficult even though theair cleaner elongates vertically.

Preferably, the air cleaner is supported in a forward slanting position.

An apparent length of the air cleaner in the vertical direction can betherefore shorter corresponding to the forward slant of the air cleaner.Thus, the seat positioned above the air cleaner can be placed at arelatively low position. Also, because of the forward slant, an upperportion of the air cleaner inevitably extends toward the space locatedin front of the seat. Therefore, the portion or the whole of the aircleaner can be inserted from the space located in front of the seatwithout being disturbed by the seat. Also, the portion or the whole ofthe air cleaner can be taken out to the space located in front of theseat without being disturbed by the seat. The attaching and detachingwork of the air cleaner becomes easier, accordingly.

By the way, in the vehicle which maintenance work for its air cleaner ismade by the approach from the lateral side location, such as themotorcycle disclosed in Patent Document 1, a space for the maintenancework is required at the lateral side location of the air cleaner. Inorder to ensure the space for the maintenance work at the lateral sidelocation, the motorcycle disclosed in Patent Document 1 has a front endof each seat rail frame positioned generally at the same height as a topend of the air cleaner. Accordingly, the front ends of the respectiveseat rail frames are placed at a relatively high position. However, thefront ends of the respective seat rail frames are portions that projectbroadly in the transverse direction. If the front ends of the respectiveseat rail frames are positioned higher as discussed, the broadly spacedportions are inevitably positioned higher. This condition can be one offactors that hinder the vehicle from being slimmer.

Therefore, preferably, the air cleaner is positioned between the spacedportions of the vehicle body frame, and an upper portion of the cleanerprojects upward more than the spaced portions.

Thus, the vehicle body frame can be positioned lower than the top end ofthe air cleaner. As a result, the vehicle becomes slimmer (the width ofthe vehicle becomes narrower).

Preferably, the air cleaner includes an air cleaner upper portion thatis positioned higher than the spaced portions of the vehicle body frame,and an air cleaner lower portion that is positioned lower than thespaced portions, and a width of the air cleaner upper portion is largerthan that of the air cleaner lower portion.

In this way, the handling of the air cleaner upper portion can beeasier, the insertion and removal of the air cleaner by the approachfrom the upper location or the obliquely front upper location can beeasier. The maintenance work for the air cleaner thus can be easier.

Preferably, the width of the air cleaner upper portion is smaller than adistance between a right end of the spaced portion on a right hand sideof the vehicle body frame and a left end of the spaced portion on a lefthand side of the vehicle body frame.

In this way, the air cleaner does not protrude beyond the vehicle bodyframe in the transverse direction. The vehicle can be slimmer,accordingly.

Preferably, the air cleaner includes a box-like cleaner case a top ofwhich opens, and a lid detachably attached to the cleaner case to blockthe opening.

In this way, the lid can be attached or detached by the approach fromthe upper location or the obliquely front upper location. Thus, themaintenance work of the air cleaner can be easily performed.

Preferably, meeting surfaces of the lid and the cleaner case incline todescend forward.

In this way, the lid can be attached or detached by the approach fromthe upper location or the obliquely front upper location. Themaintenance work for the air cleaner can be therefore easier.

Preferably, the meeting surfaces of the lid and the cleaner case extendgenerally parallel to the rear frame.

The rear frame scarcely disturbs the lid to be attached or detached. Themaintenance work for the air cleaner can be therefore easier.

Preferably, the air cleaner has a filter element built-in that ispositioned higher than the spaced portions of the vehicle body frame.

In this way, the filter element is placed at a relatively high position.The filter element can be easily cleaned or replaced with new one by theapproach from the upper location or the obliquely front upper location,after the lid is removed. Also, because the filter element and thespaced portions do not overlap with each other in the transversedirection, the distance between the spaced portions does not becomelarger even though a width of the filter element is large. The vehiclecan be slimmer, accordingly.

As described above, in accordance with the present invention, themaintenance work for the air cleaner can be made by the approach fromthe upper location or the obliquely front upper location only byremoving the seat front cover. Thus, the user can make the maintenancework in a comfortable position, and the maintenance work for the aircleaner can be easier, accordingly.

Also, if the air cleaner and the vehicle body frame are disposed in sucha manner that the upper portion of the air cleaner projects upward morethan the spaced portions of the vehicle body frame, then the vehicle canbe slimmer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of a motorcycle according to anembodiment.

FIG. 2 is a side elevational view, showing an internal structure of themotorcycle.

FIG. 3 is a partial cross sectional view of an air cleaner under amounted condition thereof

FIG. 4 is a cross sectional view, taken along the line IV-IV of FIG. 3.

FIG. 5 is a top plan view of the air cleaner under the mountedcondition.

FIG. 6 is a perspective view of the air cleaner under the mountedcondition.

FIG. 7 is a cross sectional view of a labyrinth structure.

DETAILED DESCRIPTION OF THE INVENTION

Hereunder, an embodiment of the present invention is described indetail, referring to the accompanying drawings.

As shown in FIG. 1, a straddle type vehicle according to an embodimentis a motorcycle 10 having an under bone type frame structure. Adetachable seat front cover 12 is attached below and ahead of a seat 11.The seat front cover 12 curves or bends to be a generally concave shapeas seen in a side elevational view. The seat front cover 12 defines aspace 13 that is recessed downward in front of the seat 11.

As shown in FIG. 2, the motorcycle 10 has a vehicle body frame 14, andan engine 15 supported by the vehicle body frame 14 under a suspendedcondition. The vehicle body frame 14 and the engine 15 together form avehicle body 15A. The engine 15 includes a crankcase 24 and a cylinderblock 25 obliquely extending upward forward from the crankcase 24. Thevehicle body frame 14 includes a head pipe 16, a single main frame 17, apair of a right and a left sub frame 18, a pair of a right and a leftseat rail 19 and a pair of a right and a left backstay 20.

A steering shaft, which is not shown, passes through the head pipe 16. Alower portion of the steering shaft has a front fork 22 a (see FIG. 1).A lower end of the front fork 22 a supports a front wheel 21 forrotation.

The main frame 17 is connected to a rear surface of the head pipe 16 andobliquely extends downward rearward. The main frame 17 is rectangularand hollow in cross section. However, the main frame 17 may have anyother shapes. A gusset 22 is affixed to a front half area of a bottomsurface of the main frame 17. The gusset 22 extends between the bottomsurface of the main frame 17 and the rear surface of the head pipe 16.

The sub frames 18 are affixed to respective right and left side surfacesof the main frame 17. Each sub frame 18 has a diameter smaller than thatof the main frame 17. A cross sectional area of each sub frame 18 issmaller than that of the main frame 17. The major part of each sub frame18 has a circular pipe shape in cross section. However, a flat plateshape replaces the circular shape of a front end of each sub frame 18toward the front end. The flat plate shaped portion of the front end ofeach sub frame 18 is joined with the respective side surface of the mainframe 17 by welding or the like under a condition that a surface of theflat plate shaped portion abuts on the side surface of the main frame17. Thus, the pair of the right and left sub frame 18 are connected tothe respective side surfaces of the main frame 17.

Each sub frame 18 bends in such a manner that its center portion in itslongitudinal direction extends convexly downward. A front portion (aportion ahead of the bending portion) of each sub frame 18 extendsgenerally parallel to an axial direction of the cylinder block 25 of theengine 15. A rear portion of each sub frame 18 has a slope that isgentler than that of the front portion. As discussed, the sub frames 18are shaped and disposed along the engine 15.

Each seat rail 19 is joined with the vicinity of the bending portion ofthe respective sub frame 18 by welding or the like. Thereby, each seatrail 19 obliquely extends upward rearward from the vicinity of thebending portion of each sub frame 18. Each seat rail 19 bends in such amanner that its center portion in its longitudinal direction extendsconvexly upward. Each seat rail 19 is made from a circular pipe.

Each backstay 20 is joined with a rear end of the respective sub frame18 by welding or the like. Therefore, each backstay 20 obliquely extendsupward rearward from the rear end of the sub frame 18. A rear end ofeach backstay 20 is joined with a rear end of the respective seat rail19 by welding or the like. Similarly to the seat rail 19, each backstay20 is made from a circular pipe.

The sub frames 18, seat rails 19 and backstays 20 together form a pairof a right and a left side frame. Additionally, the sub frames 18, theseat rails 19 and the backstays 20 may have any shapes other than thecircular pipe shape. The vehicle body frame 14 may be made of iron,aluminum or other materials.

A bracket 23 is affixed to the bottom surface of a rear end of the mainframe 17. The cylinder block 25 of the engine 15 is attached to thebracket 23 via bolts and nuts. Brackets 26 are affixed to the vicinityof the bending portions of the respective sub frames 18. The crankcase24 of the engine 15 is attached to the brackets 26 via bolts and nuts.Another bracket 27 is affixed to respective rear ends of the sub frames18. The bracket 27 supports both the crankcase 24 of the engine 15 andrear arms 28. As discussed, the engine 15 is supported by the main frame17 and the sub frames 18 under the suspended condition.

A front end of each rear arm 28 is supported by the bracket 27 forswinging about an axis of a pivot shaft 31. A rear end of each rear arm28 supports a rear wheel 32 for rotation. Additionally, in thisembodiment, the vehicle body frame 14 supports the rear arms 28 via thebracket 27. However, a portion of the engine 15 may supports the reararms 28.

A radiator 30 is disposed ahead of and above the cylinder block 25 ofthe engine 15 and below the main frame 17. A bracket 29 is affixed tothe gusset 22 that is affixed to the bottom surface of the main frame17. The bracket 29 supports the radiator 30.

A carburetor 33 is disposed above the crankcase 24 of the engine 15 andin the rear and the vicinity of the cylinder block 25. An air cleaner 34is disposed behind the carburetor 33. The air cleaner 34 is interposedbetween right and left separated portions of the vehicle body frame 14.That is, the air cleaner 34 is placed between the sub frame 18 and theseat rail 19 on the right hand side and the sub frame 18 and the seatrail 19 on the left hand side.

The air cleaner 34 is positioned under the seat front cover 12.Specifically, the air cleaner 34 is positioned under a rear portion ofthe seat front cover 12 (a portion that descends forward; hereunder,called forward descending portion). Thus, the seat front cover 12 coversa top of the air cleaner 34.

The air cleaner 34 includes a cleaner case 35 and a lid 36. The cleanercase 35 has a box shape such that a length thereof in a verticaldirection is longer than either a length thereof in a fore to aftdirection or a length thereof in a transverse direction. A top of thecleaner case 35 has an opening, and the lid 36 covers and uncovers theopening. As shown in FIG. 6, the lid 36 and the cleaner case 35 arecoupled together by bolts 54 positioned at four corners of the lid 36.Thus, the lid 36 can be easily attached to or detached from the cleanercase 35 by fastening or removing the bolts 54. Also, the air cleaner 34slants forward so that a top surface of the air cleaner 34 inclines todescend forward. Thus, the concave shape of the seat front cover can beeasily realized. A rider can easily get on and off the vehicle,accordingly, as described above.

As shown in FIG. 2, the air cleaner 34 is supported in a forwardslanting position so that a top end is positioned ahead of a bottom end.As shown in FIG. 3, respective meeting surfaces of the lid 36 and thecleaner case 35 extend generally parallel to the seat rails 19 and slantto descend forward. Therefore, when the seat front cover 12 is removedand the lid 36 is detached obliquely upward forward, the lid 36 can betaken out from the cleaner case 35. To the contrary, when the lid 36 isputted onto the cleaner case 35 obliquely downward rearward under thecondition that the seat front cover 12 is removed, the lid 36 can beattached to the cleaner case 35.

As shown in FIG. 4, a cross pipe 40 extends between the right and leftbrackets 27. A lower portion of the cleaner case 35 is tapered downwardand has a plurality of steps, including a step 39 (see FIG. 3). The step39 of the cleaner case 35 is supported on the cross pipe 40 via acushion rubber 41. Additionally, the cushion rubber 41 has a pluralityof pins 41 a extending downward. Those pins 41 a are inserted into thecross pipe 40.

A bracket 42 having an aperture 45 is affixed to a top of each seat rail19. Each upper portion of the respective right and left side surfaces ofthe cleaner case 35 has a sheet-like attachment 43 formed with a concaveslit 46 (see FIG. 3) therein. Each bracket 42 and the respectiveattachment 43 are coupled together by a bolt 44 passing through theaperture 45 and the slit 46.

As discussed above, the cleaner case 35 is supported by the cross pipe40 attached to the respective brackets 27 of the backstays 20 and by therespective brackets 42 of the right and left seat rails 19.

As shown in FIG. 4, a filter element 38 is enclosed in an upper space ofthe cleaner case 35. A holder 49 having a lying-T-shaped engagingportion 49 a surrounds the girth of the filter element 38. A top endperiphery of the cleaner case 35 has a groove 50 for receiving theengaging portion 49 a of the holder 49. The engaging portion 49 aengages with the groove 50 so that the cleaner case 35 detachablysupports the holder 49. Additionally, a bottom end periphery of the lid36 also has a groove 50 for receiving the engaging portion 49 a of theholder 49.

The cleaner case 35 protrudes upward above the seat rails 19. Also, asdescribed above, the cleaner case 35 is tapered downward. A width(breadth) of an air cleaner upper portion 51 positioned higher than theseat rails 19 is narrower than a width of an air cleaner lower portion52 positioned lower than the seat rails 19. Further, the width of theair cleaner upper portion 51 is shorter than a length between a rightend of the right hand side seat rail 19 and a left end of the left handside seat rail 19. That is, the air cleaner 34 is formed not to extendbeyond the right and left seat rails 19. The filter element 38 is placedin the air cleaner upper portion 51. The filter element 38 is thereforepositioned higher than the seat rails 19.

As shown in FIG. 3, an intake pipe 47 extending obliquely upwardrearward is inserted into a rear portion of the lid 36. The intake pipe47 defines an air intake section of the air cleaner 34. One end of theintake pipe 47 has an air inlet port 47 a (see FIG. 5) that opensobliquely upward rearward. Another end of the intake pipe 47 extendsinto the lid 36 and opens above the filter element 38. An air supplypipe 48 is inserted into the cleaner case 35 through a forward surfacethereof to be connected to the carburetor 33 (not shown in FIG. 3, seeFIG. 2). One end of the air supply pipe 48 opens at a location below thefilter element 38 in the cleaner case 35. Additionally, the air supplypipe 48 opens obliquely downward at a generally center position in thevertical direction. Air taken through the intake pipe 47 passes throughthe filter element 38 and is supplied to the carburetor 33 through theair supply pipe 48.

As shown in FIG. 2, the intake pipe 47 of the air cleaner 34 is disposedwithin a space surrounded by the seat 11 and the forward descendingportion of the seat front cover 12. The space above and behind theintake pipe 47 is partitioned from the external space by a wall surface75.

As shown in FIG. 5, the intake pipe 47 is flat so as to be slender inthe transverse direction. Therefore, a length of the intake pipe 47 inthe fore to aft direction is short. The intake pipe 47 is directed tosimply take the air existing behind a center portion of the air cleaner34 in the fore to aft direction. On the other hand, the intake pipe 47has a sufficient opening area, even though the length in the fore to aftdirection is short, because the length of the intake pipe 47 in thetransverse direction is long. The intake pipe 47 has a flange 55extending outward and circumferentially around an opening end.

As shown in FIG. 2, a hinge mechanism 53 is provided at a lower portionof a front end of the seat 11. The seat 11 pivots about the front end asa fulcrum via the hinge mechanism 53 to open and close.

As shown in FIG. 6, the intake pipe 47 is positioned below the hingemechanism 53. Below the hinge mechanism 53, a block 57 projects forward,and a flange 56 projects forward and sideward on both sides below theblock 57. As a result, a recess 58 concaving rearward is defined betweenthe block 57 and the flange 56. Both right and left side portions of theflange 56 slant obliquely downward rearward to form slant surfaces 56 a.

As shown in FIG. 7, the seat front cover 12 has a projection 59extending rearward. The projection 59 opposes to the recess 58 under acondition that the projection 59 is interposed between the block 57 andthe flange 56. As the result, a zigzag gap is made among the block 57,the projection 59 and the flange 56. The block 57, the projection 59 andthe flange 56 overlap with each other in the vertical direction, asdiscussed, to form a labyrinth structure 60. The labyrinth structure 60is positioned above (strictly speaking, obliquely forward upward) theintake pipe 47.

Additionally, as described above, the opening end of the intake pipe 47has the flange 55. Accordingly, not only the block 57, the projection 59and the flange 56 but also the entire combination of the block 57, theprojection 59, the flange 56 and the flange 55 function as one labyrinthstructure.

As shown in FIG. 2, a rear cushion unit 63 is disposed behind the aircleaner 34. A cross member 64 extends between the right and left seatrails 19. An upper cushion bracket 67 is affixed to the cross member 64.The upper cushion bracket 67 protrudes downward to a location below theseat rails 19. The top end of the rear cushion unit 63 is supported bythe upper cushion bracket 67.

Another cross member 65 extends between the right and left rear arms 28.A lower cushion bracket 68 is affixed to the cross member 65. The lowercushion bracket 68 supports a bottom end of the rear cushion unit 63.The lower cushion bracket 68 protrudes upward to a location above therear arms 28. Thus, the bottom end of the rear cushion unit 63 issupported by an upper portion of the associated rear arm 28 that ispositioned higher than a center position thereof (center line M of therear arm 28) in the vertical direction.

As discussed, the rear cushion unit 63 extends between the upper cushionbracket 67 and the lower cushion bracket 68. The rear cushion unit 63slants forward so that an upper supported end 69 is positioned ahead ofa lower supported end 70, and extends generally parallel to the aircleaner 34.

As shown in FIG. 2, a battery 61 is disposed behind and above the aircleaner 34, and ahead of and above the rear cushion unit 63. A fuel tank62 is disposed behind the battery 61. The battery 61 and the fuel tank62 are positioned under the seat 11. The fuel tank 62 is interposedbetween the right and left seat rails 19 to be supported by the seatrails 19.

A portion of the fuel tank 62 is positioned lower than the seat rails19. A lower portion of the fuel tank 62 projects downward to a space 73defined between the rear cushion unit 63 and the rear wheel 32. A frontportion of the fuel tank 62 has a front slant surface 71 slantingrearward while extending downward. A rear portion of the fuel tank 62has a rear slant surface 72 slanting forward while extending downward.

The upper supported end 69 of the rear cushion unit 63 is positionedahead of the fuel tank 62. A bottom end of the fuel tank 62 ispositioned lower than the upper supported end 69 of the rear cushionunit 63. That is, the top support end of the rear cushion unit 63 is offforward from the bottom end of the fuel tank 62, and the fuel tank 62and the rear cushion unit 63 partially overlap with each other in afront elevational view.

A storage box 74 for storing small articles etc. is disposed under theseat 11 and behind the fuel tank 62. A top of the storage box 74 has anopening. When the seat 11 is moved to the open position, the opening isexternally exposed. Thus, the articles can be putted into or out fromthe storage box 74 by moving the seat 11 between the open and closedpositions.

As has been described, according to the motorcycle 10, cleaning of thefilter element 38 or replacement thereof with new one can be easily madeby removing the seat front cover 12 and taking out the lid 36 of the aircleaner 34 obliquely upward forward. That is, maintenance work of theair cleaner 34 can be made by an approach from an upper location or anobliquely front and upper location. The user thus can replace the filterelement 38 with new one or can make other work without stooping orsquatting down, i.e., can make the maintenance work for the air cleaner34 in a comfortable posture of the user.

Particularly, in the motorcycle 10, because the respective meetingsurfaces 37 of the lid 36 and the cleaner case 35 incline to descendforward, and the lid 36 is putted on or taken out obliquely upwardforward, the seat 11 or the seat rails 19 do not disturb the attachingor detaching work of the lid 36. Thus, the attaching or detaching workof the lid 36 is easy, and the maintenance work of the air cleaner 34can be easily made.

Because the air cleaner 34 has the box shape that is taller than isbroad, the capacity of the air cleaner 34 can be made large withoutincreasing the length of the vehicle in the fore to aft direction or thewidth thereof. Additionally, the maintenance work of the air cleaner 34can be made by the approach from the upper location or the obliquelyfront and upper location. Thus, unlike the maintenance work made by anapproach from a lateral side location, the maintenance work is notdifficult even though the air cleaner 34 has the shape that is tallerthan is broad.

Because the air cleaner 34 is supported in the forward slantingposition, the length of the air cleaner 34 in the vertical direction(apparent length in the vertical direction) when it is set is shorterthan the length of the air cleaner 34 itself in the vertical direction.Thus, the seat 11 positioned above the air cleaner 34 can be placed at arelatively low position. Also, the air cleaner 34 can be efficientlypositioned in the narrow space under the seat front cover 12 by makingthe air cleaner 34 slant forward.

According to the motorcycle 10, the air cleaner 34 is interposed betweenthe right and left sub frames 18 and seat rails 19, and the upperportion of the air cleaner 34 protrudes upward above the seat rails 19(see FIG. 4). As discussed, because the seat rails 19 can be placed at arelatively low position, the vehicle can be made slimmer than ever.

Particularly, in the motorcycle 10, the width of the air cleaner 34 isshorter than the distance between the right end of the seat rail 19 onthe right hand side and the left end of the seat rail 19 on the lefthand side. The air cleaner 34 thus does not extend out beyond the rightand left seat rails 19. The vehicle is slimmer, accordingly, even thoughthe air cleaner 34 is positioned between the right and left seat rails19.

Also, according to the motorcycle 10, the width of the air cleaner upperportion 51 is larger than the width of the air cleaner lower portion 52.Thus, the handling of the air cleaner upper portion 51 is easier for theuser. Therefore, the maintenance work of the air cleaner 34 that is madeby approaching downward or obliquely downward can be more easily made.

The filter element 38 of the air cleaner 34 is positioned in the upperspace of the cleaner case 35. Thus, the filter element 38 can be easilycleaned or replaced with new one by removing the lid 36, without beingdisturbed by the seat rails 19 etc. Also, because the filter element 38and the seat rail 19 do not overlap with each other in the transversedirection, the distance between the right and left seat rails 19 doesnot need to be enlarged even though a width of the filter element 38becomes larger. The vehicle can be made slimmer than ever, accordingly.

Further, according to the motorcycle 10, the intake pipe 47 of the aircleaner 34 is positioned in a space surrounded by the seat 11 and theforward descending portion of the seat front cover 12 (see FIG. 2).Therefore, the intake pipe 47 is sufficiently spaced apart from thefront wheel 21 and the rear wheel 32. Thus, even if mud or the like israised up by the front wheel 21 or the rear wheel 32, the mud etc. ishardly drawn into the air cleaner 34 through the intake pipe 47.

Also, the intake pipe 47 is not only positioned higher than the frontwheel 21 and the rear wheel 32 but also opens obliquely upward forward.In this point of view, again drawing mud or the like through the intakepipe 47 hardly occurs.

Conventionally, the space surrounded by the seat 11 and the forwarddescending portion of the seat front cover 12 is the so-called deadspace that is not effectively used. Particularly, the space below thehinge mechanism 53 at the front end of the seat 11 is the dead spacethat is not effectively used. According to the motorcycle 10, however,the dead space can be effectively used as a housing space for the intakepipe 47. Also, according to the motorcycle 10, because the seat frontcover 12 is not required to be larger upward to house the intake pipe 47therein, the space 13 in front of the seat 11 is not spoiled. Thus,drawing mud or the like into the air cleaner 34 can be effectivelyprevented while enjoying advantages of the frame structure of the underbone type.

The air cleaner 34 is disposed behind the engine 15, and the intake pipe47 is positioned at the rear side of the air cleaner 34. Thus, the aircleaner 34 is interposed between the engine 15 and the intake pipe 47,and the air cleaner 34 insulates the heat from the engine 15. Hot air isinhibited from being drawn into the intake pipe 47, accordingly.Therefore, the temperature of the air supplied to the engine 15 falls,and the density of the drawn air becomes higher. The efficiency of theengine 15 increases.

Additionally, because the intake pipe 47 is directly coupled with thelid 36 of the air cleaner 34, the distance between the intake pipe 47and the air cleaner 34 is short. Thus, the resistance of the intake airon the inlet port side in the air cleaner 34 is small.

According to the motorcycle 10, the labyrinth structure 60 is locatedabove the intake pipe 47 (see FIG. 7). Therefore, even if drops of waterfall from the seat 11 when it rains or on other occasions, the labyrinthstructure 60 prevents the downward movement of the drops of water. Thedrops of water thus hardly enter the intake pipe 47, even though theintake pipe 47 opens obliquely upward. That is, water hardly enters theair cleaner 34 through the intake pipe 47.

As shown in FIG. 2, the space above and behind the intake pipe 47 isgenerally partitioned from the external space by the wall surface 75.Thus, any mud or the like can be effectively prevented from entering theintake pipe 47 from a location in the rear thereof. Additionally, thewall surface 75 may be defined by an exclusively prepared partition.Alternatively, a portion of a vehicle component may define the wallsurface 75. For example, a vehicle component such as a battery, a fueltank, a storage box or the like may be positioned behind the intake pipe47 to define the wall surface 75 with the use of a portion of thevehicle component.

Also, according to the motorcycle 10, the rear cushion unit 63 slantsrelatively steeply so that the upper supported end 69 is positionedahead of the fuel tank 62. The lower portion of the fuel tank 62projects toward the space 73 defined between the rear cushion unit 63and the rear wheel 32. Accordingly, the depth of the fuel tank 62 can bemade larger without interfering with the fuel tank 62 and the rearcushion unit 63. Particularly, according to the motorcycle 10, thebottom end of the fuel tank 62 is positioned not higher than the uppersupported end 69 of the rear cushion unit 63, and thus the fuel tank 62becomes extremely deep.

Thus, according to the motorcycle 10, the length of the fuel tank 62 inthe transverse direction or the width thereof can be smaller. Therefore,the area of the fuel tank 62 in the top plan view can be smaller, andthe degree of freedom for the layout of vehicle components under theseat 11 can be improved. Additionally, in the motorcycle 10, because thelength of the fuel tank 62 in the fore to aft direction becomes shorter,the storage box 74 that has a sufficient space is provided behind thefuel tank 62.

The lower supported end 70 of the rear cushion unit 63 is supported byan upper portion of the rear arm 28. Thus, the rear cushion unit 63 canextend along the locus of the pivotal movement of the rear arm 28 aboutthe axis of the pivot shaft 31. The suspension performance of the rearcushion unit 63 can be improved, accordingly.

The rear cushion unit 63 extends generally parallel to the air cleaner34. Therefore, the space behind the air cleaner 34 can be utilizedsufficiently. As a result, the rear cushion unit 63 and the air cleaner34 can be efficiently arranged in a limited space.

Also, according to the motorcycle 10, the battery 61 is placed in thespace defined in front of the fuel tank 62 and above the rear cushionunit 63. Thus, the space under the seat 11 is effectively used, and thefuel tank 62, the rear cushion unit 63 and the battery 61 can bearranged efficiently.

The front portion of the fuel tank 62 has the front slant surface 71that slants rearward. Thus, because the front portion of the fuel tank62 can extend along the rear cushion unit 63, any possible interferencebetween the fuel tank 62 and the rear cushion unit 63 can be avoided,even though the fuel tank 62 is deep enough. Also, the rear portion ofthe fuel tank 62 has the rear slant surface 72 that slants forward.Thus, because the rear portion of the fuel tank 62 can extend along therear wheel 32, any possible interference between the fuel tank 62 andthe rear cushion unit 63 can be avoided, even though the fuel tank 62 isdeep enough.

As thus described, the present invention is useful for straddle typevehicles including motorcycles or the like.

1. A straddle vehicle comprising: a vehicle body frame including a headpipe, a front frame connected to the head pipe and obliquely extendingdownward rearward, and a rear frame connected to the front frame andobliquely extending upward rearward, at least one of the front frame andthe rear frame having a pair of spaced portions spaced apart in atransverse direction of the vehicle; an engine including a crankcase anda cylinder block extending forward therefrom, the engine being supportedby the vehicle frame; an air cleaner positioned behind the cylinderblock and between the spaced portions in the transverse direction; aseat supported by the rear frame; and a seat front cover that isdetachably positioned below and ahead of the seat and has a concave, ina side elevational view, to define a top open space in front of the seatfor covering a top of the air cleaner, wherein a portion or the whole ofthe air cleaner is mounted to be insertable and removable by an approachfrom an upper location or an obliquely front upper location.
 2. Thestraddle vehicle according to claim 1, wherein the air cleaner has a boxshape such that a length thereof in a vertical direction is longer thanany one of a length thereof in a fore to aft direction and a lengththereof in the transverse direction.
 3. The straddle vehicle accordingto claim 2, wherein the air cleaner is supported in a forward slantingposition.
 4. The straddle vehicle according to any one of claims 1 to 3,wherein the air cleaner is positioned between the spaced portions of thevehicle body frame, and an upper portion of the cleaner projects upwardmore than the spaced portions.
 5. The straddle vehicle according toclaim 4, wherein the air cleaner includes an air cleaner upper portionpositioned higher than the spaced portions of the vehicle body frame,and an air cleaner lower portion positioned lower than the spacedportions, and a width of the air cleaner upper portion is larger than awidth of the air cleaner lower portion.
 6. The straddle vehicleaccording to claim 5, wherein the width of the air cleaner upper portionis smaller than a distance between a right end of the spaced portion ona right hand side of the vehicle body frame and a left end of the spacedportion on a left hand side of the vehicle body frame.
 7. The straddlevehicle according to any one of claims 1 to 3, wherein the air cleanerincludes a box cleaner case a top of which opens, and a lid detachablyattached to the box cleaner case to block the opening.
 8. The straddlevehicle according to claim 7, wherein, meeting surfaces of the lid andthe box cleaner case incline to descend forward.
 9. The straddle vehicleaccording to claim 8, wherein the meeting surfaces of the lid and thebox cleaner case extend generally parallel to the rear frame.
 10. Thestraddle vehicle according to claim 7, wherein the air cleaner has afilter element built-in that is positioned higher than the spacedportions of the vehicle body frame.